For example, we've seen listings in Marketplace for snakes, baby hedgehogs, fish, a farm hand, and scantily clad people posing suggestively. (More examples are at the bottom of this story.)

A Facebook spokesperson declined to comment to Business Insider beyond pointing us to the company's Commerce Policy, which expressly prohibits selling these kinds of items and services.

To police what is sold, the spokesperson did say that Facebook will rely on its employees proactively looking for offensive posts in Marketplace along with users reporting posts they think should be removed.

Facebook has been testing Marketplace with a small percentage of its users for months, but now the feature is replacing the Messenger shortcut in the bottom center of Facebook's app for everyone over the age of 18 in the U.S., U.K., Australia, and New Zealand.

Update: Facebook director of product management Mary Ku later told Business Insider that a "technical issue" caused these listings to get past its review process. She said the company is "working to fix the problem" and "closely monitoring our systems to ensure we are properly identifying and removing violations before giving more people access to Marketplace."